The present invention relates to a manifold.
As disclosed in Japanese Laid-Open Patent Publication No. 2016-91845, a fuel cell mounted on a vehicle such as an automobile is equipped with a manifold, which causes fluid, specifically, fuel gas, oxidation gas, and coolant to flow through the cell stack of the fuel cell. The fuel cell is cooled by coolant supplied to and discharged from the cell stack via the manifold, while generating power using fuel gas and oxidation gas supplied to and discharged from the cell stack via the manifold.
Such a manifold has a metal end plate attached to a case of the fuel cell that is provided to surround the cell stack. The end plate has an opposed surface facing an end in the cell stacking direction of the cell stack, a recess, which opens in the opposed surface and forms a flow path through which coolant flows, and ribs protruding from the bottom surface of the recess to the opening position of the recess on the opposed surface. Furthermore, the opposed surface, the recess, and the ribs in the end plate are covered by a plastic layer.
When the end plate is fixed to the case, the portion of the plastic layer that covers the opposed surface and the portions of the plastic layer that cover the distal end faces in the protruding direction of the ribs contact the end in the cell stacking direction of the cell stack. This causes the cell stack to be pressed in the cell stacking direction by the opposed surface, so that a favorable cell stacking structure of the same cell stack is maintained. At this time, the opening of the recess formed in the opposed surface of the end plate is closed by the end in the cell stacking direction of the cell stack, which forms a flow path through which coolant flows in the recess. The end in the cell stacking direction of the cell stack is cooled by the coolant flowing in the flow path.
The fluid in the flow path and the end plate are insulated from each other by a portion of the plastic layer that covers the inner surface of the recess and the outer surfaces of the ribs. The end plate and the cell stack are insulated from each other by the portion of the plastic layer that covers the opposed surface and the portions of the plastic layer that cover the distal end faces in the protruding direction of the ribs.
The end in the cell stacking direction of the cell stack is cooled by the coolant flowing in the flow path in the recess, which is formed in the opposed surface of the end plate. However, the portions of the end that contact portions of the plastic layer that cover the distal end faces in the protruding direction of the ribs do not easily contact the coolant in the flow path and therefore cannot be effectively cooled.